diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 74cc9cefb6d..da31b3e5eb9 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -2063,11 +2063,16 @@ fs_visitor::register_coalesce_2()
 	  inst->src[0].smear != -1 ||
 	  inst->dst.file != GRF ||
 	  inst->dst.type != inst->src[0].type ||
-	  virtual_grf_sizes[inst->src[0].reg] != 1 ||
-	  virtual_grf_interferes(inst->dst.reg, inst->src[0].reg)) {
+	  virtual_grf_sizes[inst->src[0].reg] != 1) {
 	 continue;
       }
 
+      int var_from = live_intervals->var_from_reg(&inst->src[0]);
+      int var_to = live_intervals->var_from_reg(&inst->dst);
+
+      if (live_intervals->vars_interfere(var_from, var_to))
+         continue;
+
       int reg_from = inst->src[0].reg;
       assert(inst->src[0].reg_offset == 0);
       int reg_to = inst->dst.reg;
@@ -2091,31 +2096,13 @@ fs_visitor::register_coalesce_2()
       }
 
       inst->remove();
-
-      /* We don't need to recalculate live intervals inside the loop despite
-       * invalidating them; we only use them for the interferes test, and we
-       * must have had a situation where the intervals were:
-       *
-       *  from  to
-       *  ^
-       *  |
-       *  v
-       *        ^
-       *        |
-       *        v
-       *
-       * Some register R that might get coalesced with one of these two could
-       * only be referencing "to", otherwise "from"'s range would have been
-       * longer.  R's range could also only start at the end of "to" or later,
-       * otherwise it will conflict with "to" when we try to coalesce "to"
-       * into Rw anyway.
-       */
-      invalidate_live_intervals();
-
       progress = true;
       continue;
    }
 
+   if (progress)
+      invalidate_live_intervals();
+
    return progress;
 }
 
diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
index 41176c74236..50aa7a62ae3 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.cpp
@@ -244,6 +244,12 @@ fs_live_variables::compute_start_end()
    }
 }
 
+int
+fs_live_variables::var_from_reg(fs_reg *reg)
+{
+   return var_from_vgrf[reg->reg] + reg->reg_offset;
+}
+
 fs_live_variables::fs_live_variables(fs_visitor *v, cfg_t *cfg)
    : v(v), cfg(cfg)
 {
@@ -334,6 +340,13 @@ fs_visitor::calculate_live_intervals()
    }
 }
 
+bool
+fs_live_variables::vars_interfere(int a, int b)
+{
+   return !(end[b] <= start[a] ||
+            end[a] <= start[b]);
+}
+
 bool
 fs_visitor::virtual_grf_interferes(int a, int b)
 {
diff --git a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
index fa14eecd897..82575d8287f 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
+++ b/src/mesa/drivers/dri/i965/brw_fs_live_variables.h
@@ -66,6 +66,9 @@ public:
    void compute_live_variables();
    void compute_start_end();
 
+   bool vars_interfere(int a, int b);
+   int var_from_reg(fs_reg *reg);
+
    fs_visitor *v;
    cfg_t *cfg;
    void *mem_ctx;